全文获取类型
收费全文 | 21653篇 |
免费 | 2371篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 160篇 |
儿科学 | 723篇 |
妇产科学 | 815篇 |
基础医学 | 3017篇 |
口腔科学 | 553篇 |
临床医学 | 2557篇 |
内科学 | 4763篇 |
皮肤病学 | 304篇 |
神经病学 | 1681篇 |
特种医学 | 754篇 |
外科学 | 2616篇 |
综合类 | 447篇 |
一般理论 | 35篇 |
预防医学 | 2281篇 |
眼科学 | 343篇 |
药学 | 1972篇 |
中国医学 | 11篇 |
肿瘤学 | 1027篇 |
出版年
2021年 | 287篇 |
2020年 | 187篇 |
2019年 | 328篇 |
2018年 | 359篇 |
2017年 | 282篇 |
2016年 | 293篇 |
2015年 | 321篇 |
2014年 | 480篇 |
2013年 | 633篇 |
2012年 | 948篇 |
2011年 | 977篇 |
2010年 | 511篇 |
2009年 | 476篇 |
2008年 | 842篇 |
2007年 | 993篇 |
2006年 | 918篇 |
2005年 | 902篇 |
2004年 | 893篇 |
2003年 | 822篇 |
2002年 | 802篇 |
2001年 | 733篇 |
2000年 | 804篇 |
1999年 | 668篇 |
1998年 | 253篇 |
1997年 | 219篇 |
1996年 | 220篇 |
1995年 | 238篇 |
1994年 | 210篇 |
1993年 | 201篇 |
1992年 | 524篇 |
1991年 | 542篇 |
1990年 | 521篇 |
1989年 | 516篇 |
1988年 | 474篇 |
1987年 | 488篇 |
1986年 | 440篇 |
1985年 | 408篇 |
1984年 | 357篇 |
1983年 | 290篇 |
1982年 | 227篇 |
1981年 | 186篇 |
1979年 | 285篇 |
1978年 | 277篇 |
1977年 | 197篇 |
1976年 | 201篇 |
1975年 | 193篇 |
1974年 | 209篇 |
1973年 | 175篇 |
1972年 | 201篇 |
1970年 | 172篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Autoimmune diseases are a significant problem in women of reproductive age. This article reviews some of the more common autoimmune disorders and discusses their diagnosis and management during pregnancy. The effects of the autoimmune disorder on pregnancy and the effects of pregnancy on the course of the autoimmune disorder are also discussed with an emphasis on the implications for clinical management. 相似文献
52.
A 25-yr-old female triathlete presented with 4 d of increasing left calf pain that started 1 d after an elective termination of pregnancy during the eighth week of gestation. She had been training with running, bicycling, and swimming but did not recall any injury to the calf muscle. Deep venous thrombosis of the calf and popliteal veins was diagnosed, and she was treated with intravenous heparin and oral warfarin anticoagulation. Her major concern was return to training and competition. A protocol was developed based on experience with less active patients and animal studies to allow a progressive return to training activities over 5 wk, followed by running in the sixth week. After release from the hospital, she accelerated the return-to-training protocol and progressed to running within 3 wk. She developed the post-phlebitic syndrome that resolved within 2 yr. The diagnosis and treatment of deep venous thrombosis are reviewed, with specific attention to the needs of athletic patients. 相似文献
53.
Maturational changes in retinal excitatory amino acid receptors 总被引:1,自引:0,他引:1
The appearance, kinetics and pharmacological properties of receptors for n-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA), kainate (KA), L-glutamate (Glu) and L-aspartate (Asp) was investigated using 3H-ligand binding during the development of chick embryo retina. Receptors for AMPA are maximally concentrated at embryonic day 7 (ED 7) and decline 50% in subsequent days; L-Glu receptors are low until ED 11, and the same is true for Asp and NMDA receptors which increase at ED 14 and 18 respectively. All receptors studied underwent an increase in pharmacological specificity, whereas only AMPA-receptors showed an important change in affinity during ontogeny. Results demonstrate that receptors for excitatory amino acids in the retina suffer maturational changes and suggest that while NMDA and aspartate could interact with the same receptor, AMPA and glutamate seem to bind to different sites. 相似文献
54.
Certain clinical and autopsy findings are described in 13 patients who had both aortic dissection (AD) and fusiform abdominal aortic aneurysm (AAA). All 13 patients had severe and extensive aortic atherosclerosis. The AAA was diagnosed clinically in 9 patients, and 5 had the AAA resected. The AD was diagnosed clinically in 5 patients, and 2 underwent attempted operative repair. Two patients who had the AAA resected because of suspected rupture were found later to have ruptured a more proximal AD. Thus, AD occurs occasionally in patients who have AAA. In older persons with suspected rupture of an AAA, a more proximal rupture of an AD should be ruled out. When both AAA and AD are present in the same patient, the AD is more likely the cause of cardiovascular collapse than is rupture of the AAA. 相似文献
55.
In male rats, there is an age-associated decline in the capacity of cardiac sympathetic nerves to release norepinephrine. To investigate whether this phenomenon also occurs in female rats, we examined adrenergic neurochemical transmission in the hearts of female and male Fischer 344 rats. Rats aged 6, 12, and 24 months were employed. Hearts with the right cardiac sympathetic nerve intact were isolated and perfused with Krebs-Ringer solution. Stimulations were performed following the administration of cocaine or metanephrine separately and in combination or following the combination of cocaine, metanephrine, and yohimbine. Cocaine (1 microM) was used to block uptake 1, metanephrine (1 x 10(-5) M) to block uptake 2, and yohimbine (3 microM) to block alpha 2 receptor presynaptically. The nerve was stimulated with frequencies of 2, 6, and 12 Hz, and norepinephrine amount in the effluent was determined by high performance liquid chromatography/electrochemical detection methods. Neither norepinephrine release nor the effects of yohimbine, cocaine, or metanephrine were found to be affected in older female rats (24 month). This suggests that age-related changes in adrenergic neurochemical transmission in the heart of female rats differ from those seen in older male rats. 相似文献
56.
A R Salkind D O McCarthy J E Nichols F M Domurat E E Walsh N J Roberts 《The Journal of infectious diseases》1991,163(1):71-77
Respiratory syncytial virus (RSV) infection has been shown to induce human mononuclear leukocyte (MNL) production of net interleukin-1 (IL-1)-inhibitor activity. In the current studies of IL-1-inhibitor effects, RSV-exposed cells were compared with autologous MNL that were sham-exposed or exposed to inactivated RSV or influenza virus (which induces net IL-1 activity and commonly elicits effective homotypic immunity). Exposure of MNL to influenza virus or inactivated RSV resulted in increased expression of human leukocyte antigen-DR, the IL-2 receptor, and the transferrin receptor and increased progression through the cell cycle by 3 days. In contrast, exposure to infectious RSV resulted in decreased marker expression and cell cycle arrest, with abrogation of proliferation in response to the virus or other stimuli. These data raise the possibility that a contributing mechanism for recurrence of RSV infection is early suppression of the clonal expansion of virus-specific lymphocytes due to net IL-1-inhibitor activity. 相似文献
57.
A postal audit of the main surgical variables in third molar exodontia under general anaesthesia was undertaken on consultants holding a National Health contract within the British Isles. This first paper presents the results. A response rate of 175 returned questionnaires from the 247 consultants was obtained (70.9%). Analysis revealed that the majority of consultants use antibiotics, mouthwashes, sutures, analgesics and postoperative review and the minority steroids and peroperative local anaesthetic, routinely in the majority of cases. Approximately half routinely use a chisel as opposed to a bur for bone removal. The consultants who gave all their patients steroids were significantly (p less than 0.01) more likely to possess a medical qualification than the consultants who did not. 相似文献
58.
59.
60.